Invalid MIT-MAGIC-COOKIE-1 key (gksudo:2984): Gtk-WARNING **: cannot open display: :0

Question

when i run tuxcut,i see this message i try this command and not run tuxcut

user@server:~$ xhost +localhost
su -
Defaults env_keep=DISPLAY
xhost +localhost &
xhost +SI:localuser:root &
gksudo "lxterminal --command "nano /etc/default/grub""

how i solve this issue?

Answer 1

Use su without the dash. That will keep the XAUTHORITY environment variable intact.